Ultra high frequency generator



Sept. 18, 1951 H. DIAMOND ULTRA HIGH FREQUENCY GENERATOR Filed July 11, 1940 \NVENTOR 0WD WW ATTO R N EY a portion of the resonators.

Patented Sept. 18, 1951 ULTRA HIGH FREQUENCY GENERATOR Hymen Diamond, Pittsburgh, .Pa., 'assignor to Westinghouse Electric Corporation, East Pitts ..Recent1y,ultra-high frequency generators have been developed in which hollow body resonators are interposedin the path of the charges ina discharge device. In such resonators, thefree quency is dependent on the dimensions of..the resonators and can only be varied by changing the resonator dimensions. For proper operation ofthe generator, the resonators must be tuned and therefore their dimensions must be varied. Since the resonators are subjected to the dis charge in a vacuum, difiiculty has been experiencedintuning them. v n

Itis one of the objects of my invention to provide a tuning means capable of accurate adjust mentfor the resonators of any ultra-high frequency generator. I n a Another object of my invention is to' provide suitable tuning means for the 'resonatorsof Ian ultra-high frequency generator. v A general object of my invention is to'provide a method for precisely tuning a hollow body resonator'.

In accordance with the broad aspects of'my invention, the resonant frequency of 'a'hollow body resonator may be changedbyvarying its temperature. Specifically, my invention contemplates the external'elect'rical control of a movable Preferably, a hollow body resonator is provided with a vane supported from a lever which changes its position under the influence of heat. The lever may be provided with an electrical heater, the temperature of which may be controlled externally. I Other aspects and advantages of the invention .will be apparent from the following description and drawing in which: I

Fig. 1 is a view partly in cross section and partly diagrammatic of a preferred embodiment of my invention, applied to an ultra-high frequency apparatus utilizing hollow body resonators.

Fig. 2 is a view on lines IIII of Fig. 1 b I In Fig. l, I have disclosed a particular type of ultra-high frequency apparatus utilizing hollow space resonators for which my tunin means is especially adapted, although my invention may be applied to other type of high-frequency apparatus.

The apparatus shown in the drawing comprises a cylindrical metallic container 1 of a suitable vacuum-tight material such as copper or steel,

Since substantial heat is developedvin the eontainer and must necessarily be dissipated it is burgh, Pa 'corporationof Pennsylvania Application July- 11, 1940, Serial No. 344,832

provided with external cooling coils 3 through which a cooling medium such as water may be conducted. y-

electron-emissive cathode assembly 5 is supported from an insulating ring I secured to an end wall of the container. The cathode assembly 5 comprises a heater 9 enclosed within an emissive cap I I, the outer surface of which is covered by a readily emissive material such as a combination .of alkaline earth oxides. The cap II is flanged and the flanges I3 are supported on a dish-shaped disc I5 having a perforation I6 at its center through which the heater 9 extends. A-potential of the order of several thousan volts is'impressed between the emissive cap I I and ground from a suitable source [1 which; may be of the usual commercial 60 cycle type. The container I isalso grounded and the potential which is thus impressed between the container wall and the cathode cooperates with the dishshaped electrode I5 to convert the electrons emitted from the cap II into a narrow high velocity stream. A conducting partition I9 with an openwork 2| at its center is secured to the cylindrical wall of the container I a short distance from the cathode 5. The partition is at ground potential, and it accelerates the electrons in the stream. The stream passes through the openwork 2| and then, after moving across a narrow gap 23, passes through another openwork 25 which forms one endof a hollow conducting cylinder 21. The cylinder 21 is supported from a second partition 29 which is centrally disposed in the container I andto. which it is secured coaxial with the container I. The supporting partition 29 is provided with a gap 3| adjacent one region of the wall of container I, and a vane 33 supported from a rod 35 extends into the gap. The rod 35 supporting the vane is secured to a special adjusting and control means hereafter more fully described.

The cylinder 2! provides a field-free space through which the electron stream moves in an axial direction. The stream passes out of the cylinder through the remote end 39 which is also an openwork and then moves across another narrow gap 4 I. The openwork 43 of a third partition 45 is in the path of the stream at the end ofthe gap 4| and the stream passes through it and impinges on a deflecting electrode 41. The deflecting electrode 41 is suspended from a plur'alityot symmetrically disposed insulators 49 secured to the rear end of the container I so that its. axis is coincident with the axis of the 0on tainer. It is composed of a, material that has a motion of the electrons in the stream and the latter are, therefore, deflected to the container wall where they are dissipated. 1

In passing through the gaps 23 and 4| and the cylinder 21 the energy imparted to the stream by the source I! is converted into high frequency radiant energy. The region bounded by the first partition [9, the openwork 25, the 'wall of the cylinder 21 between the central partition 29 and the openwork 25, the partition 29- and the wall of the container I between the partitions l9 and 29 including the portion of the vane 33 therein,

29 constitutes a hollow body resonator, one of the resonant frequencies is that which is radiated. The resonator is excited to oscillate at the selected; f requency and: as the electron stream passes through the gap.-- 23. within the resonator; the electrons are influenced by the electric field corresponding tothe excitation. of the resonator. The electric vector of'the field causes a periodic variation of longitudinal velocity at the. frequency of the field. This variable velocity is superimposed'on-the average velocity corresponding tothe D.-C. voltage applied between. the cathode and the metallic body of the resonators. The'electrons therefore, move at different speeds they pass into the field-free spacewithin the cylinder 21. As the electrons move through the cylinder-,- the collect" in groups at predetermined positions because the fast electrons tend to catch up with the slow ones.

The cylinder2'i is of such length that theelectrons-are=bunched in groups when they pass through the openwork 39-intothe adjacent gap 41; The gap-M is a portion of the region ofa hollow bod resonator bounded bythe partition CS-[the adjacent openwo'rk 39 of; the cylinder 21, the wall of the cylinder 2! between the-central partition 29 and the openwork 39, the central partition 29 and the wall of the container I. betweenthe partition and thelower parti- Hon-"45' including'the' portion of the vane 33 to the right of the central partition. 4

The last-mentioned resonator is preferably dimensioned the same as the resonatorbetween theupper partition Iii and the central partition 29.50 thatone of its resonant frequencies is the same as the selected frequency of the latter. Slight differences in frequency may be compensated by regulating the control; means- 31, hereafter described, to the extent that the vane 33 moves farther into, the first or second resonator as indicated by. the arrows.

The resonator including the gap 41 is thus excited to oscillate at the same frequency, as the resonator containing the other gap 23. By proper choice of D.-C'; voltage andilength. of cylinder 21 the groups of electrons are made. to cross the gap M at the time, when the; electric field, at this gap 41 retardjstheir'motion. The electrons, therefore, give up a. substantial fractl'on of their kinetic energy to the field-jand the energy is. converted into'radiant energy.

V The energy is radiated by means of a suitable antenna which is fed through a transmission line'5l comprising a shielded elongated conductor 5.3sealed through the containerl having a'jloop 55. extending into the energy-generating resonator with the gap 4i. The-loop is: oriented so that it is threaded by the magnetic vector of the electromagnetic field within the resonator. The first resonator with the gap 23 whereby the velocity of the electron stream is modulated, is excited to oscillate by a loop 5! which extends between the two resonators through an opening 54 in the separator wall of the central partition 29. This is the usual feed-back connection where the apparatus is used primarily to produce oscillations. Where the apparatus is used for amplifying purposes, the modulating resonator with the gap 23 may be excited to oscillate by a proper source of high frequency oscillations.

The electron stream does not give up the total energy to the energy-generating resonator with the gap 4|. After passing through the latter resonator, the stream is deflected by the insulated electrode 41 to the wall of the container l where the charge is dissipated.

- In order to tune the two hollow resonators containing the gaps 23 and 4|, I provide a copper plate 33 vertically extending. through. a1sl0t-I3l in the common partition 29 between the. two hollow resonators. Thisplate or vane 33- is connected by 35 to a bimetallic strip having its other end supported at 6| in an insulating casing 62 secured and sealed tothe casing around the opening 63, through which the connecting: rod 35 extends. The bimetal St issurrounded by-a heating coil Ki l connected toelectrical heating means 65 controlled by rheostat 66. Whenever the tuning between the twohollow resonators is to be varied, the heatingof the bimetal is regulated bythe rheostat 66 to move the copper vane 33 up further into the-first hollow resonator or down into the second hollow resonator, as desired. It is apparent that the bimetallic strip must be pre-set' to place the vane 33-rnainly' in one resonator so that the application of heat will move it first to the positionillustrated and then move it into theother resonator.

I have accordinglyv disclosed a tuning'means for the, hollow resonators which is especially suitable for asealed-oficasing and one that is both positive and accurate in making the variation desired in the tuning, of the apparatus.

In addition to. the. elements included in the arrangement described herein the apparatus may incorporate any contrivances used generally in the. cathode ray. art in the same connection (such as improved. processing devices) without departing from the scope of the invention.

The temperature of the bimetal 6| need'not necessarily be controlled by an electric heater 64. The casing 62 may be immersed in a constant temperature bath and the temperature of' the bath may be controlled as desired. Moreover, the whole generator may be immersed in a constant temperature bathand the tempera; ture of. the latter bath may be adjusted. Since large variations intemperature produce substantial variation in the dimensions of a hollow body, adjustments may be efiected' without the vane 33 by immersing the generator in a bath which may-=be varied betweena very low temperature as, for example, that-ofiliquidair oroxygemand a hightemperature. The-bimetal fi'l mayunder certain conditions be replaced by a single-cle ment. of highthermal expansi-vity.

Although I have shown and described a' c'e'r tain specific embodiment of my invention, 1 am fullyaware that many modificationsthereofiare possible. Myinvention, therefore;- is not'to bare-- stricted exceptinso faras is necessitated -by thespirit oftheappendedclaimsa 1 I claim:

1. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, a plurality of hollow body resonators in said discharge path, a metal part adapted to move into said hollow body resonators, and means for moving said metal part, said means including electrical conductors sealed through said container.

2. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, a plurality of hollow resonators adjacent one another in said discharge path, a metal part adapted to move into either of said hollow body resonators, and means for moving said metal part, said means including electrical conductors sealed through said container.

3. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, a plurality of hollow body resonators in said discharge path having a common partition, a metal part in an opening in said common partition adapted to move into either of said hollow body resonators, and means for moving said metal part, said means including electrical conductors sealed through said container.

4. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, a plurality of hollow body resonators in said discharge path, a metal part adapted to move into said hollow body resonators, a bimetal supporting said metal part,

and electrical heating mean about said bimetal for controlling the movement of said metal part.

5. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, a plurality of hollow body resonators adjacent one another in said discharge path, a metal part adapted to move into either of said hollow body resonators, a bimetal supporting said metal part, and electrical heating means about said bimetal for controlling the movement of said metal part.

6. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, a plurality of hollow body resonators in said discharge path having a common partition, a plate of metal in an opening in said common partition adapted to move into either of said hollow body resonators, a bimetal supporting said plate and electrical heating means about said bimetal for controlling the movement of said plate.

7. An electric discharge device comprising an envelope, means for producing a stream of electrical charges in said envelope, a hollow-body resonator interposed in the path of said stream, a portion of said resonator being capable of change in position to vary the resonant frequency of said resonator, thermal means connected to said portion for changing the position of said portion to vary the resonant frequency of said resonator, and electrical conductors sealed through a part of said envelope for electrically controlling said thermal means.

8. An ultra-high frequency device comprising a container, a plurality of electrodes therein defining a discharge path, hollow-body resonator means in said path, said resonator means in cluding a portion movable relative to remainder of said resonator means, means actuatable in response to temperature changes for moving said portion relative to said remainder, and temperature varying means cooperative with said actuatable means for determining the position of said portion.

9. An electric discharge device comprising a hollow-body resonator, a cathode, and means for bunching electrons emitted from said cathode and causing the bunched electrons to give up energy in said resonator, in combination with mechanical means for altering the distributed capacity and inductance of said resonator and thermal means for actuating said mechanical means.

10. An electric discharge device comprising an evacuated envelope, said envelope providing a hollow-body resonator, a cathode in said envelope for directing electrons through said resonator, means for bunching electrons and causing the bunched electrons to give up energy in said resonator, mechanical means within the evacuated envelope and in part within said resonator for altering the distributed capacity and inductance of said resonator, and thermal means for actuating said mechanical means.

11. An electric discharge device comprising an evacuated envelope, said envelope providing a hollow-body resonator, a cathode in said envelope for directing electrons through said resonator, means for bunching electrons and causing the bunched electrons to give up energy in said resonator, mechanical means within the evacuated envelope and in part within said resonator for altering the distributed capacity and inductance of said resonator, and electrically heated thermal means for actuating said mechanical means.

12. An electric discharge device comprising an evacuated envelope, said envelope providing adjacent hollow-body resonators, a cathode in said envelope for directing electrons through said resonators and causing the bunched electrons to give up energy in one of said resonators, mechanical means partly in each resonator and movable with respect to each so that withdrawal thereof from one resonator introduces more of said means into the other resonator for equating the resonant frequency of the two resonators, and thermal means for moving said mechanical means.

HYMEN DIAMOND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,559,714 Lilienfeld Nov. 3, 1925 1,884,591 Davis Oct. 25, 1932 2,079,809 Kuhle et al. May 11, 1937 2,133,642 Pierce Oct. 18, 1938 2,162,478 Diamond June 13, 1939 2,243,537 Rayn May 27, 1941 2,263,184 Mouromtseff et a1. Nov. 18, 1941 2,323,735 Tawney July 6, 1943 2,374,810 Fremlin May 1, 1945 OTHER REFERENCES Journal of Applied Physics, vol. 10, No. 5, May 1939 (pp. 321-327). 

